Water Density and Temperature

As water warms, it expands.* At 50° F a pound of water has a volume of 15.37 ounces.
However, a 150° F pound of water has a volume of 15.86 ounces.
Let's look at a water density versus temperature plot.

The plot shows that water density decreases as temperature increases.
Warm water weighs less than cool water. Does this match your experience? If you dive
down into a lake, even on a very cloudy day, the water becomes cooler. The warm water
is on top because it is lighter.